The term “mortice lock” generally refers to a lock which is designed to be inserted into the edge of a door (i.e. inserted into a space or “mortice” in the door's side edge) rather than being mounted on the inside or outside surface of the door. Mortice locks typically have one or more latches or bolts which can project from the lock, through the side edge of the door, to engage with a strike or some other part of the doorframe when the door is closed. The latches/bolts therefore retain the door closed and must be retracted back into the lock to allow the door to be opened.
A wide range of mortice lock designs have been proposed and used in the marketplace. They range from relatively simple locks which provide a basic level of security to higher end locks which provide a greater level of security. It should be appreciated that just because the “simple” locks provide a lower level of security, this does not mean they are inferior to the higher end locks. Indeed, different applications call for locks with differing levels of security, and in some situations a simple lock which provides a lower level of security would be preferable or more suitable. Of course, there are also situations in which a higher level of security is preferable or required.
Because different locks providing differing levels of security are often required in different situations, it is generally necessary for lock manufacturers to produce a range of locks. Locksmiths and architectural hardware suppliers must also carry a range of different locks. This can create problems, particularly where (as often) the different locks all use different mechanisms and components. In this situation, the lock manufacturer must be equipped to manufacture a very large range of different components in order to construct all the different locks, and locksmiths etc must carry and stock a large range of components and locks. This creates significant cost, stock handling difficulties and other problems for lock manufacturers, locksmiths and other architectural hardware suppliers. It would be preferable if a range of locks could be provided in which the basic components remain common (or mostly so) between the different locks in the range so as to minimise the number of different components that must be manufactured and handled. Naturally, higher end locks which provide a greater level of functionality and/or security may often need additional components to achieve this, but these additional components should preferably mostly “build on” the components of the lower level locks and substitution of low end lock components for alternative components in higher end locks should preferably be minimised.
In general, simple mortice locks which provide a relatively low level of security typically have only one bolt (typically a latch bolt) which extends out from the lock to engage with the strike/doorframe to maintain the door closed. Retracting this latch bolt allows the door to be opened. In order to properly be called a “lock” (as opposed to a non-lockable “latch”), the lock should incorporate some mechanism which can prevent retraction of the latch bolt (or at least prevent use of the handle to retract the latch bolt). Often, this mechanism will incorporate a key cylinder.
More secure locks often have multiple bolts. Most typically there will be 2 bolts—one latch bolt and one deadbolt. Both bolts need to be retracted in order to open the door. Normally, when the door is closed, only the latch bolt will automatically extend out to engage with the strike or doorframe to maintain the door closed (this automatic extension of the latch bolt when the door is closed is often called “self-latching”). However, if desired, the user can also operate the lock (typically by using a key cylinder) to extend the deadbolt and this generally deadlocks the lock.
Furthermore, even higher-end locks often operate as part of a multipoint lock assembly. These locks typically incorporate a latch bolt and deadbolt as just described, but they also have one or more remote bolts which are located above and/or below the main lock. Each remote bolt can be extended out to engage with a separate part of the doorframe to provide additional security.
Mortice locks have been provided which have a range of different operating modes. For the purposes of this specification, it is useful to describe three different modes. Importantly, not all mortice locks necessarily have all of these modes. Also, the function of some mortice locks may not accord precisely with the following description (i.e. some locks may have modes which do not exactly fit the description of some/any of the modes given below).
One of the modes may be referred to as the “passage mode”. In the passage mode, it is possible to operate the door handle on either side of the door to open the door. Another mode may be referred to as the “safety mode”. In the safety mode, a key is required to open the door from the outside (i.e. it is not possible to open the door from the outside simply by operating the door handle without first operating the lock with a key). However, in the safety mode the key is not necessarily required to open the door from the inside. In other words, in the safety mode, it is possible to operate the lock from the inside to allow the door to be opened without the need for a key. Finally, the third mode may be referred to as the “secure mode” or the “deadlocked” mode. In the secure mode, a key is required to open the door from either side (i.e. it is not possible to open the door from either side without first operating the lock with a key).
One particular mortice lock is described in Australian Patent Application No 2004229071. The lock described in Application 2004229071 is a fairly high end lock. It has a latch bolt, a deadbolt, and a pair of “shoot bolts” which can extend out from the top and bottom of the lock respectively to operate upper and lower remote bolts.
The latch bolt, deadbolt and shoot bolts are all operated by the door handle in Application 2004229071. The handle connects (via a spindle) to a drive cam, which in turn connects to a drive gear. The drive cam pivots coaxially with the drive gear about the axis of the spindle, but there is a degree of free pivotal motion between the drive cam and drive gear. The drive cam has a portion which engages directly with the latch tongue such that rotation of the drive cam from its neutral position in one direction (a first direction) causes linear retraction of the latch tongue. Hence, when the lock is in the passage mode, it is possible to rotate the handle(s) in that first direction which then rotates the drive cam thereby retracting the latch tongue. However, rotating the handle(s) and retracting the latch tongue in this way does not cause the drive gear to rotate (due to the free motion mentioned above).
When the lock in Application 2004229071 is in the passage mode, it is also possible to rotate the door handle(s) from the neutral position in the other direction (i.e. a second direction). Rotating the handle in the second direction does not cause any interaction between the drive cam and the latch bolt, so the latch bolt remains extended. However, rotating the handle(s) in the second direction causes the drive cam to rotate the drive gear (both rotate coaxially in the second direction). The drive gear has a series of teeth which mesh with corresponding teeth on the pivotable deadbolt. Consequently, rotating the handle in the second direction causes the drive gear teeth to pivot the deadbolt extending it out of the lock (i.e. this “throws” the deadbolt).
Throwing the deadbolt in Application 2004229071 in the way described in the previous paragraph also has the effect of extending the shoot bolts mentioned above. The shoot bolts each have a slot which attaches to a lug on the pivotable deadbolt. The lug to which the upper shoot bolt attaches is located forward of the deadbolt's pivot point, and the lug to which the lower shoot bolt attaches is located behind the deadbolt's pivot point. Consequently, as the deadbolt rotates out of the lock, this rotation pushes the upper shoot bolt upwards in the lock, and the lower shoot bolt is pushed downwards. This causes the respective shoot bolts to extend from the top and bottom of the lock to operate the remote bolts (the remote bolts connect to the shoot bolts by connecting rods). When the shoot bolts are thus extended, a portion on the upper shoot bolt engages with the extended latch bolt preventing the latch bolt from being retracted (either by using the handles or in an unauthorised manner using jemmy etc) while the shoot bolts (and deadbolt) are extended.
In Application 2004229071, if it is desired to retract the shoot bolts (and hence the remote bolts) and deadbolt, this can be done simply by rotating the door's handle in the first direction (assuming the lock is not “deadlocked” as described below).
Rotating the door's handle back in the first direction causes the drive cam to rotate the drive gear (both rotate in the first direction) and the teeth on the drive gear mesh with the teeth on the deadbolt to rotate the deadbolt back into the lock. This reverse rotation of the deadbolt causes the lugs on the deadbolt to pull the shoot bolts back into the lock.
The lock in Application 2004229071 also has a deadlock member. The deadlock member can only be operated using a key, and then only when the deadbolt has been thrown (which also extends the shoot bolts—as described above). The deadlock member cannot be operated when the deadbolt is retracted into the lock because, in this position, a curved ridge on the deadbolt presses against the deadlock member to prevent any movement of the deadlock member in the lock. However, when the deadbolt is thrown, the curved ridge moves out of the way of the deadlock member.
The reason it is only possible to operate the deadlock member using a key is because the deadlock member has a spring-loaded component which engages on one side of an internal ridge on the lock casing (the ridge is actually on the inside of the lock's cover plate). This prevents the deadlock member from moving in the deadlocking direction. The only way to disengage the spring-loaded component from this ridge is by turning a key in the key cylinder which causes the key cylinder's cam to initially push the spring-loaded component (against the spring bias) out of engagement with the ridge so it can move past the ridge. Further rotation of the key (and hence the cylinder cam) pushes the deadlocking member upwards in the lock into the deadlocked position. In the deadlocked position, a portion of the deadlock member engages with the drive cam to prevent rotation of the drive cam. Hence, when the lock is thus “deadlocked” (i.e. placed in the secure mode), it is not possible to rotate the handle(s) in the first direction to withdraw the latch bolt, deadbolt or shoot bolts. A key is therefore required to operate the lock from either side. Also, when the deadlock member moves into this deadlocking position, the spring-loaded component engages on the other side of the above-mentioned internal ridge thereby preventing the deadlock member from moving back towards the un-deadlocking position except if the key is again used to push the spring-loaded component out of engagement with the ridge and slide the deadlock member back into the un-deadlocking position.
Whilst the lock in Application 2004229071 is able to be used in a multipoint lock assembly that provides a high level of security, it has a number of limitations in terms of functionality. For instance, it isn't possible to operate the key to deadlock the lock unless and until the handle has been operated to throw the deadbolt and extend the shoot bolts. Also, the deadbolt and shoot bolts are extended and retracted together. It would be preferable if the lock could be operated to extend one or the other of the deadbolt and shoot bolts independently, or so that the lock can have both extended together, as desired. Furthermore, assuming the lock in Application 2004229071 has a key cylinder into which a key can be inserted from either side of the door (as normal), the operation of the lock is identical from either side. That is, the lock is either in the passage mode in which it is possible to operate the handle from either side to retract the latch bolt or throw the deadbolt and shoot bolts, or it is in the secure (“deadlocked”) mode in which case a key is required to operate the lock from either side. The lock does not provide a safety mode in which a key is required to operate the lock from the outside but not necessarily from the inside.
The lock in Application 2004229071 also has shortcomings in terms of its versatility and its ability to be converted or adapted to create a lower level (less secure) lock. Indeed, it would be very difficult to adapt the lock for use as a single point lock (i.e. a lock with only the latch bolt) because the entire locking mechanism in Application 2004229071 involves the operation of the pivotable deadbolt. It would even be difficult to adapt the lock for use as two point lock (i.e. a lock having a latch bolt and a deadbolt but in which there is no need for the shoot bolts to operate the remote bolts) because removing the shoot bolts from the lock in Application 2004229071 would require the lower end of the deadlock member (and possibly also lower end of the lock casing) to be reconfigured, and a new mechanism would also be required for preventing the latch bolt from retracting when the lock is deadlocked (as noted above, this is presently achieved by a portion on the upper shoot bolt which engages with the latch bolt when the upper shoot bolt is extended).
It is an object of the present invention to help to address one or more of the above-mentioned disadvantages, or at least provide a useful or commercial alternative to mortice locks currently available in the marketplace.
It will be clearly understood that mere reference herein to previous or existing locks or other information (including publications) or problems does not constitute an acknowledgement or admission that any locks, other material(s) or information of any kind, or problems, or any combination thereof, formed part of the common general knowledge in the field, or is otherwise admissible prior art, whether in Australia or any other country.